The invention pertains to a mold for the casting of metals, in particular, for low-pressure casting, with at least two mold parts which are in contact with one another in a parting plane and with a feeder channel, which extends through one of the mold parts, is secured in the area of the parting plane and is connected to the mold cavity by at least one inlet channel.
In a known mold of this type (DE-OS No. 20 37 652, FIG. 7) the feeder channel is bolted to the lower mold part by means of attachment flanges which are parallel to one another and perpendicular to the parting plane in a manner creating an intermediate space therebetween. In this process, the high casting temperatures can cause warping and buckling of the feeder channel, which is rigidly secured at both of its longitudinal sides to the lower mold part. This can have the effect that the mold will no longer close tightly so that liquid metal will discharge in the area of the parting plane. Additionally, this metal can also seep through gaps into the intermediate space which is provided for the purpose of heating the feeder channel and is located between the mold part and the feeder channel. In both cases, smooth operation is no longer ensured.
Thus, a principal object of the invention is to create a mold with a feeder channel of the type mentioned in the introduction in which the feeder channel can expand better without leaking.
This object is achieved in accordance with a preferred embodiment of the invention due to the fact that the essentially trough-shaped feeder channel is clamped between the two mold parts by means of an attachment flange which is essentially parallel to the parting plane; in this process, the flange engages with one of the two mold parts in the area of the inlet openings in such a way as to seal the mold, and elsewhere the flange is unattached at its outer edge.
Because of these measures, the feeder channel is securely anchored to the adjacent mold part in the area of the inlet channels, i.e., on the ingate side. In this area, which is particularly prone to the discharge of liquid metal, gaps are completely avoided due to the fact that the edge of the feeder channel engages with the mold part in such a way as to seal against the mold. Since, with the exception of the ingate side, the attachment flange of the trough-shaped feeder channel is only clamped between the two mold parts and the outer edge of the flange is unattached, i.e., is not restrained anywhere, the attachment flange can expand parallel to the parting plane under the action of the high casting temperatures; in this process, it is still quite possible to ensure the sealing of the flange with respect to the adjacent mold parts.
In the preferred practical implementation of the invention, the fact that the attachment flange engages in such a way as to seal against the mold secures this flange approximately parallel to the parting plane with respect to the mold part and vertically with respect to the longitudinal extension of the flange. This can be preferably achieved with the aid of a spline-like key, which runs parallel to the attachment flange, is inserted into an approximately horizontal support shoulder of the lower mold part and engages in a channel on the underside of the attachment flange. Therefore, the attachment flange can expand in its longitudinal direction; in this process, perpendicular to the longitudinal extension of the flange, the mold sealing engagement which is required for good ingate-side sealing is retained, and this engagement secures the flange to the adjacent mold part of the ingate side without leaving any gap.
It is a good idea for the attachment flange to be secured on the ingate side at one point in its longitudinal extension in such a way that it seals the mold. This reliably secures the feeder channel in its position. Since the attachment flange is secured at only a single point, however, the flange can still expand from this point in both longitudinal directions.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, a single embodiment in accordance with the present invention.